Characterization and in situ Biodegradation Analysis of Brown Kraft Paper Coated with PHA for Potential Sustainable Packaging§.

Research background: Biodegradable packaging is gaining immense research interest as conventional non-biodegradable food packaging has led to significant environmental pollution. In response to this, this study aims to develop biodegradable films based on polyhydroxyalkanoate (PHA) as potential food packaging material.

Experimental approach: Polyhydroxyalkanoate (PHA) homopolymer, poly(3-hydroxybutyrate) [P(3HB)] and copolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)], known microbial biodegradable biopolymer plastics, were layered in different mass ratios using the dispersion coating technique over the brown kraft paper as a food packaging material. PHA are known to be safe, non-cytotoxic and non-genotoxic, with a remarkable ability to biodegrade in the environment. The P(3HB) and P(3HB-co-3HV) were synthesised from carbon sources of palm olein and a combination of palm olein with 1-pentanol, respectively, using Cupriavidus malaysiensis USMAA2-4_ABH16, a transformant bacterial strain with acquired lipase genes.

Results and conclusions: Contact angle analysis indicated that brown kraft paper coated with P(3HB-co-3HV) had a higher contact angle than uncoated brown kraft paper and paper coated with P(3HB). The biodegradation analysis of brown kraft paper coated with P(3HB) showed that it degraded 100 % within 9 days compared to all samples of brown kraft paper coated with P(3HB-co-3HV), which were completely degraded by day 12.

Novelty and scientific contribution: The results show that brown kraft paper coated with P(3HB-co-3HV) was more hydrophobic than uncoated and P(3HB)-coated brown kraft paper. This study encourages further investigations of brown kraft paper coated with PHA to develop biodegradable food packaging, paving the way for a sustainable alternative to non-biodegradable packaging material.